Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
  • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
  • G01N21/64—Fluorescence; Phosphorescence
  • G01N21/6486—Measuring fluorescence of biological material, e.g. DNA, RNA, cells
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
  • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
  • G01N21/64—Fluorescence; Phosphorescence
  • G01N21/645—Specially adapted constructive features of fluorimeters
  • G01N21/6456—Spatial resolved fluorescence measurements; Imaging
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J1/00—Photometry, e.g. photographic exposure meter
  • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
  • G01J1/44—Electric circuits
  • G01J2001/4413—Type
  • G01J2001/442—Single-photon detection or photon counting
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
  • G01J1/00—Photometry, e.g. photographic exposure meter
  • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
  • G01J1/44—Electric circuits
  • G01J2001/4446—Type of detector
  • G01J2001/4493—Type of detector with image intensifyer tube [IIT]
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
  • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
  • G01N2021/635—Photosynthetic material analysis, e.g. chrorophyll
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/84—Systems specially adapted for particular applications
  • G01N2021/8466—Investigation of vegetal material, e.g. leaves, plants, fruits
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2201/00—Features of devices classified in G01N21/00
  • G01N2201/02—Mechanical
  • G01N2201/022—Casings
  • G01N2201/0221—Portable; cableless; compact; hand-held
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N2201/00—Features of devices classified in G01N21/00
  • G01N2201/08—Optical fibres; light guides
  • G01N2201/0826—Fibre array at source, distributing

Definitions

• Phytoluminography is two dimensional imaging of phytoluminescence using high sensitivity light amplifiers. The technique was first described by Sundbom and Bjorn i 1977. Its use in early detection of plant stress has bee frequently described in Soviet literature. A few selected references are listed:
• the present invention uses easily available electronic flashguns with xenon flashlamps to excite luminescence in leaves. Green leaves exposed to other types of light such as sunlight, fluorescent light, incandescent light will also exhibit this phenomenon. However, these sources of illumination are non-uniform in spatial intensity distribution, spectral emission pattern, non-reproducible and not suitable for quantitative work.
• the preferred configuration of the electronic flashgun would be in the form of a ring light for ease of incorporation into the phytoluminometer and uniform distribution of light when used with a diffuser. Other configurations would work for less critical applications.
• the light source can be used in a white light (polychromatic) mode. It can also be filtered with glass or gelatin filters for monochromatic mode.
• Xenon flashlamp sources may be operated at varying repetition rates for luminescence lifetime studies. Planar electroluminescent lamps are suitable for less intense excitation. Solid state laser diode sources can be used after beam expansion and can be pulsed. Two dimensional arrays of light emitting diodes (LEDs) can be used but provide nonuniform illumination.
• LEDs light emitting diodes
• the leaf surface is viewed by the light amplifier assembly without delay after luminous excitation with the source of excitation switched off.
• the leaf surface is placed or held directly against the planar input surface of a fused, coherent, rigid, fiberoptic light pipe, taper or flexible fiberoptic bundle.
• Gradient index (GRIN) self -focussing fibers may be used in the fiberoptics.
• a fiberoptic taper allows minification or magnification depending upon the application.
• Conventional air coupled lenses may be used if provided with piano concave fiberoptic faceplates to optimize coupling between the leaf and the light amplifier. Projection of the image of the leaf using standard focal length lenses is not acceptable because of severe transmission losses.
• the surface coupled to the light amplifier should be of a piano type again to reduce coupling losses. Reflection losses caused within the coupling of polished planar surfaces are reduced by the use of optical greases such as Dow Corning Silicon Grease # Q2-3067 optimized for refractive indices of the glasses.
• the light amplification can be performed with first, second, or third generation image intensifiers of the types commonly used in night vision devices.
• Second generation image intensifiers are preferred because of optimal spectral match between the phytoluminescent emission and the photocathode spectral response.
• Proximity focused, electrostatic inverter, gated or nongated image intensifiers with one or more microchannel plates may be used.
• Multistage, low noise amplification with luminous gains greater than 10 8 is necessary for imaging the entire luminescence decay. This necessitates cascading at least two second generation image intensifiers.
• Hybrid types with second generation intensifier at the input end and first generation at the output end can be used but are currently twice as expensive.
• All of the above image intensifiers can be procured with self contained battery operated power supplies and automatic bright source protection and can be gated. All of them are available with piano fiberoptic input and output faceplates. This facilitates ease of coupling to imaging optics and to each other.
• the entire assembly is encased in a light tight aluminum or plastic housing.
• the material of the enclosure is not critical as long as phosphorescent or fluorescent materials are excluded.
• the batteries for operating the flashgun, image intensifiers as well as the variable gain controls, switches are external to the light tight enclosure.
• the intensifie image may be viewed in subdued light, recorded with conventional 35mm, Polaroid, still or movie film, video, analog or digital cameras. Analog images may be digitize for image storage, processing, analyses, transmission by us of commercially available software and hardware. Th intensified image may be quantified in its entirety or fraction thereof using optical to electrical probes i conjunction with oscilloscopes or photometers.
• Figure 1 is a schematic of one type of phytoluminograph apparatus using prior art.
• Figure 2. is a schematic of a second type of phytolumi nography apparatus using prior art.
• Figure 3. is a schematic of a third type o phytoluminography apparatus using prior art.
• Figure 4. demonstrates a schematic of the phytoluminometer using the current invention.
• Figure 5. represents a "second generation" image intensifier comprising multi-alkali photocathode, an electrostatic focussing system, a microchannel plate (MCP) as electron multiplier and a luminescent screen positioned immediately behind the MCP.
• MCP microchannel plate
• a high voltage power supply operating from low voltage batteries is included in the encapsulation.
• Figure 6 represents a proximity focussed gated image intensifier with MCP and a gating power supply. This enables the tube to be switched within 5 nanoseconds for rapid electronic shuttering during luminescence lifetime studies.
• the present invention is a process and apparatus for obtaining quantitative images of luminescence arising from plant leaves and other surfaces excited by an external source of light.
• the luminescent light distribution represents active sites of photosynthesis. Perturbation of photosynthesis caused by darkness, high concentrations or lack of C0 2 , lack of 0 2 , extremes of temperatures, noxious gases, chemicals, bacterial, viral, and fungal infections, * can be rapidly and easily demonstrated using this invention.
• the perturbed area will manifest itself as brighter than non-perturbed area if recoverable, and darker if irreversibly damaged. These changes are visible with the instrument described herein seconds after the damage and days or weeks before the damage is visible to the unaided eye. Consequently, this invention helps in very early detection of plant stress and prediction of recovery.
• FIG 4 refers to the schematic of the present invention.
• the excitation source A for illuminating the leaf is shown as an electronic flashgun with the xenon filled tube in a ring form.
• the light from the ring flash is diffused by a .Lucite disc B within the ring.
• the Lucite disc B also serves as a support for the leaf D to be studied.
• Narrow or wide band, glass or gelatin filter C may be interposed between the Lucite support and the leaf D for monochromatic excitation.
• the power source E for the ring flash A is battery operated and external to the assembly X.
• the mechanical or electronic switch F allows either the excitation source A or the light amplifier G and H to be operational thus preventing damage to the light amplifiers- by inadvertent exposure to high intensity light.
• the imaging optic K is a fiberoptic taper with planar large and small surfaces. In operation leaf D on support B is directly in contact with the front surface L of the taper K. The rear surface M of the taper is coupled to the front fiberoptic faceplate N of the first stage image intensifier 0.
• the rear fiberoptic output phosphor P of the first stage image intensifier is coupled directly to the front fiberoptic faceplate Q of the second stage image intensifier R.
• the output phosphor S of the second stage intensifier R is not covered by the enclosure X and thus is visible to the eye.
• the output phosphor S can also be coupled to optical cameras.
• the power source for the image intensifiers is provided by the batteries T ' - ' .. providing power to E as well. All fiberoptic coupling surfaces should use a thin layer of Dow Corning Q2-3067 optical couplant taking great care to exclude air bubbles. This reduces reflection losses, maintains tight but removable contact between surfaces and is immune to humidity, temperature changes.
• the image intensifier tubes used in this apparatus should have the highest available photocathode sensitivity, in the spectral emission band of phytoluminescence, bes signal to noise ratio, lowest equivalent backgroun illumination (EBI) , minimum number of blemishes, hot spots. Standard military grade image intensifiers used in nigh vision devices are not preferred. Astronomical grade tube should be specified. Second generation tubes with high output type (HOT) MCPs are preferred. When research applications with luminescence lifetime detection are involved fast output phosphors such as P-ll should be specified for the image intensifiers. Multi-colored current sensitive phosphors such as PT-452 will provide good contrast discrimination without computer enhancement.
• EBI equivalent backgroun illumination
• gated wafer tubes may be used in the first or second stage for rapid electronic switching of light amplification and for protection during strobing. It is preferable to operate photocathode and output phosphor surfaces close to ground potential to eliminate arcing, ion flashes, leakages between opposing coupled surfaces.
• a thin conductive coating with optical transparency such as tin oxide (NESA) should be applied to output fiberoptics for grounding it.
• the entire assembly is encased in a light tight plasti or metal enclosure with care taken to exclude all fluorescent or phosphorescent materials such as paints, adhesives, detergents, optical brighteners.
• the low voltag battery power supply and adjustable gain controls for th image intensifiers are located outside the light enclosure but are connected to it by a cable or mounted on it. Th switching functions and gain control can be-controlled by a computer for nonportable applications.
• the manual gai controls should preferably be ten turn, wire woun potentiometers with turns indicator dial for precise setting and resetting of gain.
• the video signal may be digitized for image acquisition, storage, analyses, quantitation, and enhancement.
• the hardware and software for accomplishing these functions are widely available commercially and need not be described here.

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• Health & Medical Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Immunology (AREA)
• Biochemistry (AREA)
• Pathology (AREA)
• Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
• Physics & Mathematics (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• General Physics & Mathematics (AREA)
• General Health & Medical Sciences (AREA)
• Biomedical Technology (AREA)
• Engineering & Computer Science (AREA)
• Molecular Biology (AREA)
• Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
• Transition And Organic Metals Composition Catalysts For Addition Polymerization (AREA)
• Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)
• Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)

Applications Claiming Priority (3)

Publications (2)

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• 1993
  • 1993-10-21 US US08/140,278 patent/US5406089A/en not_active Expired - Lifetime
• 1994
  • 1994-10-19 AU AU80516/94A patent/AU687114B2/en not_active Ceased
  • 1994-10-19 EP EP94931430A patent/EP0725930A4/de not_active Withdrawn
  • 1994-10-19 WO PCT/US1994/012089 patent/WO1995011443A1/en not_active Application Discontinuation
• 1995
  • 1995-01-20 US US08/376,000 patent/US5576550A/en not_active Expired - Fee Related

Patent Citations (3)

Non-Patent Citations (3)

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